1. A steam engine converts 150 kg of water completely to steam. The process involves transfer of 4 x 10^8 J as heat. If steam escaping through the safety valve does 2 x 10^8 J of work against outside atmosphere, the net change in the internal energy is:
a. 2 J
b. 2 x 108 J
c. 6 J
d. 6 x 108 J
Work to transformed water to steam = 4*10^8 J
Work to overcome safety valve=2*10^8 J.
Both work are added to the internal energy.
To find the net change in the internal energy, we need to consider the heat transferred and the work done.
The net change in internal energy (ΔU) is given by the equation:
ΔU = Q - W
Where:
ΔU = Net change in internal energy
Q = Heat transferred
W = Work done
In this case, the heat transferred (Q) is given as 4 x 10^8 J, and the work done (W) is given as 2 x 10^8 J.
Substituting these values into the equation, we get:
ΔU = 4 x 10^8 J - 2 x 10^8 J
Simplifying, we have:
ΔU = 2 x 10^8 J
Therefore, the net change in internal energy is 2 x 10^8 J.
The correct answer is b) 2 x 10^8 J.